1. Field of the Invention
This invention relates to a method and apparatus for restoring cores, and more particularly, cores utilized for accommodating a roll of paper.
2. Description of the Prior Art
Newsprint and other paper used for printing is generally shipped from the paper mill in large rolls. When the rolls are made up at the paper mill, they are wound on a tubular core. Typically the cores are made of liner board and are usually provided with metal caps of the type described in U.S. Pat. No. 5,271,258, issued Dec. 21, 1993 to Bernier et al.
In the press room or other printing plant, the roll is mounted on an unwind apparatus with the core of the roll journaled on mandrels. Once the web of paper has been unwound from the core, the core is generally discarded or returned to a paper mill to be recycled as waste fiber. The core caps are first removed and restored for further use or sold for scrap.
The paper rolls are wound and unwound at high speeds and are, therefore, susceptible to misalignment while being wound, resulting in improper registry on the printing press, requiring constant alignment correction. A slight inconsistency in the outer diameter of 0.25 inches will cause the paper web, when being wound, to move away from the end of the core that includes the portion with the larger diameter. It is important, therefore, that the outer diameter be constant and retain its circular cylindrical configuration. Likewise, the inner diameter must not vary so that the axis of rotation is at the true center of the core and thus the roll of paper. Any out-of-center rotation will cause similar winding and unwinding problems.
Thus, it has not been contemplated to reuse a winding core once it has been utilized once other than to cut the core down to a smaller size. It has been found that after a single use, the winding core has been somewhat damaged. Even though such damage may appear negligible, the distortions in the outer diameter or center of rotation are usually unacceptable. Thus, the practice in industry is to discard the winding cores once a roll of paper web has been unwound therefrom. The discarded single use winding core is then returned to the paper mill as scrap liner board to be recycled as paper fiber.
It is an aim of the present invention to reclaim discarded winding cores and to restore such cores to acceptable standards such that the restored winding core can be reused as a winding core.
It is a further aim of the present invention to provide a method for restoring winding cores.
It is a further aim of the present invention to provide an apparatus to economically restore such discarded winding cores.
It is a still further aim of the present invention to provide an improved winding core with superior dimensional parameters compared to conventional winding cores.
A method in accordance with the present invention comprises the steps of collecting used winding cores, passing each core through a station for trimming the ends of each core, passing each core through a coning station for centering the core in relation to its outer diameter, grinding the outer surface of each core to a constant diameter equivalent to an outer diameter standard less the thickness of a finishing web of fiber material, providing a finishing web of fiber material with a length corresponding to the length of the winding core being restored and having a width equal to the circumference of the core being restored, and wrapping the finishing web of paper about the core being restored.
In a more specific embodiment of the present invention, the method includes the steps of recuperating used cores, selecting the winding cores by grade and length, passing each core through a core tip puller station for removing the steel tips from the ends of the cores, trimming the ends of the cores to remove crimping portions thereof, passing each core through a coning station for centering the cores in relation to their outer diameter, forming a female joint socket at one end thereof and a complementary male joint socket at the other end thereof, joining the cores end to end with adhesive to form an elongated multiple-length core master, grinding the outer surface of the core master to a constant diameter equivalent to a predetermined outer diameter standard less the thickness of a finishing web of paper, providing an elongated web of finishing material equivalent to the length of the multi-length core master, and wrapping the web about the core with adhesive so as to provide a constant outer diameter equivalent to the predetermined standard, and then cutting the multi-length core master to desired core lengths.
An apparatus in accordance with the present invention comprises a cutting table for trimming the ends of each winding core wherein saw means are provided for cutting off the ends of each core in order to remove any crimping marks, a coning station downstream of said cutting table wherein coning means are provided for centering the individual cores in relation to their outer diameters, grinding means for grinding the outer surface of the core to a predetermined constant diameter, and means for wrapping a finishing web of paper on the ground surface of the core, including a table for laying an elongated web of finishing paper having a length corresponding to the length of the core and a width corresponding to the circumference of the core, and means for wrapping the finishing web of paper on the core with adhesive.
An apparatus in accordance with a more specific embodiment of the present invention comprises a cutting table having a pair of spaced-apart cutting saws whereby the distance between the cutting saws can be adjusted to the equivalent of the length of the core being trimmed less the accumulated length of the portions of the ends to be trimmed, a coning station including a pair of spaced-apart heads each adapted to engage opposite ends of a trimmed core for the purpose of forming complementary female and male joints on the opposite ends of the core, means downstream of the coning station for joining the cores end to end to form a master core of a predetermined length representing multiple cores, a grinding station being arranged downstream thereof and including feeding means for feeding the so-formed master core by a rotating grinding wheel for grinding the core to a predetermined constant outer diameter, and the means for wrapping a finishing web of paper including a skiver for skiving the longitudinal edges of the web of finishing paper, means for applying glue to one surface of the web to be in contact with the core, the web wrapping station including a table, a web feeder for feeding a predetermined length of web onto the table from a continuous roll, means for picking up and laying the core master on the web, means for wrapping the length of web about the circumference of the core master with the skived edges overlapping, and means for cutting the core master into predetermined core lengths.
In another aspect of the present invention, there is provided an apparatus for wrapping a layer of material about a cylinder including an elongated frame, a material web feeding means at one end of the frame for feeding a predetermined length of web of material horizontally and longitudinally of the frame, the web having a width equal to the circumference of the cylinder, glue means for applying adhesive to the web, means for picking up and positioning a cylinder over the web of material on the elongated frame so that the axis of the cylinder is parallel to the longitudinal axis of the web of material, means for bringing the web of material and the cylinder into contact such that the adhesive will engage the surface of the cylinder, and means for rotating the cylinder so that the web of material is wrapped completely about the cylinder.
A winding core for transporting a web of paper in accordance with another aspect of the present invention comprises a circular cylindrical tube having ends and a predetermined circumference, the tube having a first spiral fiber board substrate and a web of fiber board material having a length equal to the length of the tube and a width corresponding to the circumference of the tube, the web of material having skived longitudinal edges, wherein the web of material is wrapped about the tube and forming a longitudinal seam made up of the longitudinal skived edges of the web that have been overlapped.